Conversion of hydrocarbons



Aug. 15,1944.

G. EGLOFF ETAL CONVERSION OF HYDROGARBONS Filed Jan. 27, 1941 lllIKINVENTOR GUSTAV EGLOFF MASLI KOMAREWSKY TTORNEY treatment.

Patented Aug. 15, 1944 UNITED STATE s v PATENT. OFFICE CONVERSION OFHYDROCABBONS Gustav Eglofl and Vasili Komarewsky, Chicago,

111., assignors to Universal Oil Products Company, Chicago, 111., acorporation of Delaware Application January 27, 1941, Serial No. 376,030

4 Claims. (Cl. 196-54) This invention is concerned with the conversionof relatively heavy fractions of petroleum, such as the gas oilfractions, into substantial yields of gasoline of both a high antiknockand a saturated character.

The invention is more specifically concerned with the treatment of heavyfractions of petroleum' with a metal halide catalyst in a combination ofsteps involving a primary cracking treat ment followed by anisomerization treatment of the cracked gasoline which comprisesessentially a reforming operation without the occurrence of saturatedgasolineof relatively high antiknock value which comprises continuouslytreating said heavy fractions with aluminum chloride andhydrogen'ehloride to produce substantial yields of gasoline boilingrange products, fractionatin conversion products to produce gases,gasoline,

intermediate insufficiently converted refluxes and residual material,recovering said gases and said residual material, returning saidinsufllciently converted refluxes to further conversion, subiecting saidgasoline to further treatment with aluminum chloride and hydrogenchloride to imundesirable amounts of decomposition" reactions resultingin losses of gas and heavy carbonaceous residues.

It is recognized as being known in the art to use metal halides ascatalysts in cracking heavy distillate fractions of etroleum to producegasoline boiling range materials therefrom. In genin the formation ofvarying yields of'hydrocarbons having both monoand di-oleilnlcunsaturation. The gasoline boiling range from these types of operationsfrequently require special supplementary treatments to render thegasoline marketable in ,respect to color and gum formation and stabilityin respect to antiknock value on storage in refineries in contact withair.

Such supplementary treatments include treat: ment with sulfuric andother acids, hydrogenation, inhibitors and many other methods of Whilethe gasoiines produced by aluminum chloride cracking, as typical ofprocesses employing various catalytically active metal halides, areessentially saturated, we have found that benefits are obtained if thegasoline primarly produced is subjected to further treatment ,with metalhalides having an isomerizing action on the hydrocarbons in the primarygasolines. The magnitude of these effects will be developed later in thepresent description in connection with the examples introduced. g

In one specific embodiment thepresent invention comprises a process forconverting relatively heavy hydrocarbon fractions containingsubstantially no gasoline into substantial yields of prove the antiknockvalue thereof, fractionating the products from the gasoline treatment toproduce gas, isomerized gasoline and residual materials'consisting offractions amenable to further conversion and partly spent aluminumchloride, separately recovering said gas and said isomerized gasolineand returning said residual material to the primarytconversion zone.

The essential steps of the present process will be developed inconnection with the attached drawing which shows by the use ofconventional figures in side elevation an arrangement of interconnectedunits by which the process may be carried out. The drawing is not madeto any absolute or relative scale and is merely used to illustrate thegeneral type of flow which-characterizes the process of thepresent'invention.

Referring to the drawing, a hydrocarbon charging stock such as apetroleum gas oil fraction or naphtha is introduced to the plant througha line I containing a valve 2 to a charging pump 3 which discharges intoline 4 containing a valve I and thence through a heating element I 8disposedto receive heat from a furnace l1. The necessary amounts ofsubstantially anhydrous aluminum chloride may be introduced in the formof a slurry in a substantially unreactive hydrocarbon fraction by way ofline 8 containing a'valve I to charging pump 8 which discharges throughline 9 containing a valve I ll into line 4. The hydrogen chlorideessential for the conversion reactions is introduced through. line I lcontaining a valve ii to charging pump or compressor l3 which dischargesthrough line It containing 'a valve I! to line l.- Line 4 also receivesprimary cracked refluxes'from line 3i and secondary refluxes from line15 along with artly spent catalysts.

The proportions of hydrocarbons, aluminum{ 4 chloride and hydrogenchloride are selected to produce optimum eyeball results, but ingeneral, the amounts of aluminum chloride will be less than 10% of theweight of the oil, and the amounts of hydrogen chloride will -be of theorder of from 1 to 5% of the weight of the oil. While the hydrogenchloride is thus evidently. in minor amounts its presence isnevertheless essential to the conversion reactions.

During the passage of the mixture of oil, aluminum chloride and hydrogenchloride through.

heating element l6 it is brought to some temperature in the approximaterange of about 300- fect the desired separations. Line 26 containing avalve 21 is provided for withdrawing spent catalyst and the process ispreferably operated so that the residual material retains sufiicientfiuidity to permit continuous withdrawal and recovery of the activecatalyst or other decomposition products.

The vapors from lower section 2| pass through line 22 containing a valve23 to theupper portion of the fractionating column which is preferablyoperated so that mixed gases containing lessthan four carbon atoms permolecule are withdrawn through line 24 containing a valve 25 whilebutanes are withdrawn through line 33 containing a valve 34 and thepentane fraction through line 35 containing a valve 36. Th refiuxesamenable to further catalytic conversion may be withdrawn through line26 containing a valve 29 to recycling pump 30 which discharges throughline 3| containing a valve 32 back to charging line 4.

In accordance'with the present invention, a gasoline fraction, say oneboiling between the approximate range of IOU-400 F. is removed as I aside-cut through line 31 containing a valve 38 to a pump 39 whichdischarges through a line 40 containing a valve 4| through a secondaryheating element 52 disposed to receive heat from a forming step are fromabout 125 to about 500 F.,.and pressure may beemployed if desired toincrease the capacity of the unit although apparently pressure has verylittle independent affect. Rates of flow will also required adjust--ment.to'give the propertime of contact for efiecting optimum treatment.

The products from heating element 52 pass through lin 54 containing avalve 55 to a final fractionator 56 adapted to segregate fixed gases,gasoline boiling range fractions and heavy recycled materials. Line 51containing a valve 58 permits the'withdrawal of fixed gases which can befurther fractionated if desired to separate hydrogen chloride forrecycling "to either step of the process, although means foraccomplishing I these ends are not shown in the drawing. Gasolineboilingrange. materialsof improved ,antiknock value ar withdrawn throughline 59 containing a valve 50 and passed through condenser SI and thenceto line 62 containing a valve 63 to receiver 64 which is'shown providedrials will usually consist of a small amount ofheavy reflux containingpartly spent suspended aluminum chloride. Since when operations areproperly conducted there is a minimum of side reactions in th secondstep of the process the aluminum chloride slurry withdrawn through line69 will still have potency in effecting the primary cracking reactions.Pump H discharges into line 12 containing valves 13 and 14 and havingbranch line 15 containing a valve I6 for recycling reflux to line 4.Valve 14 may be used to intermittently or continuously-purge a certainamount of the spent catalyst if found desirable or necessary.

furnace 53. In a manner analogous to the prie mary conversion step,aluminum chloride either in a finely divided condition as such or on asupport may be introduced as a relatively concentrated slurry by way ofline 41 containing a valve 48 to pump "which discharges through a linecontaining a valve 5| into line 40. Requisite amounts of hydrogenchloride essential for the succeeding isomerization treatment may beintroduced through line 42 containing a valve 43 to feed pump orcompressor 44 which discharges through line 45 containing a valve 46into line 40.

The conditions necessary for further isomerizing the hydrocarbons in theprimary gasoline to raise the over-all antiknock value thereof willagain .vary with such factors as the type of oil originally charged tothe plant, the degree of conversion and the susceptibility of theindividual hydrocarbons to isomerizing treatment so that only broadranges orconditions can be laid down. While itis probable thatisomerization reactions predominate in the secondary reforming step ofthe process, it is probable thatother reactions tak place to addto theoverall reforming affect. These reactions may involve carbon to carbonsplitting, dehydrogenation, particularly of naphthenes, and varioustypes of alkylation and hydrogen transfer reactions.- The range oftemperatures most commonly employed in the re-' The following example isintroduced as illustrative of the results normally obtainable in theoperation of the present process although not with the intention oflimiting the invention in exact correspondence with the data presented.-

.A.Mid-Continent gas oil fraction was subjected to treatment, thecracking step being conducted at a temperature of 575 F. in the presenceof about 10% ,by weight of finely divided granular and substantiallyanhydrous aluminum chloride and about 5% by weight of hydrogen chloride.In this stage of the process there was produced 46% of gasoline byvolume of the oil charged, this gasoline having an octane number of 69by the motor method of testing. This gasoline fraction was furthertreated with 6% byweight of granuhydrocarbon fraction containingsubstantially no gasoline into substantial yields of saturatedgasolineof relatively high antiknock value which comprises cracking said heavyfraction in the presence of aluminum chloride and hydrogen chloride in aprimary conversion zone to produce substantial yields of gasolineboiling range products, fractionating conversion products to producegases, gasoline, intermediate insufficiently converted refiuxes andresidual material, recovering said gases and said residual material,returning said insufiiciently converted refiuxes to further conversion,subjecting said gasoline to further treatment with aluminum chloride andhydrogen chloride to improve the antiknock value thereof,- fractionatingthe products from the gasoline treatment to produce gas, isomerizedgasoline and residual material consisting of hydrocarbon fractionsamenable to further cracking and partly spent aluminum chloride,separately recovering i said gas and said isomerized gasoline andreturning said residual material to the primary conversion zone.

2. -A process for converting a relatively heavy hydrocarbon fractioncontaining substantially no gasoline into substantial yields ofsaturated gasoline of relatively high antiknock value vwhich comprisescracking said heavy fraction at temperaturespf from about 300 to about700 F. under a pressure of from 50 to about 400 pounds per square inchin the presence of aluminum chloride and hydrogen chloride in a primaryconversion zone to produce substantial yields of gasoline boiling rangeproducts, fractionating conversion products to produce gases, gasoline,intermediate insufliciently converted refluxes and residual material,recovering said gases and said residual material, returning saidinsufllciently 'converted refluxes to further conversion, subjectingsaid gasolineto further treatment at a temperature of from about 125 toabout 500 F. with aluminum chloride and hydrogen chloride to improve theantiknock 'value thereof, fractionating the products from the gasolinetreatment to produce gas, isomerized gasoline and residual materialsconsisting of hydrocarbon fractions amenable to further cracking andpartly spent aluminum chloride, separately recovering said gas and saidisomerized gasoline and returning said residual material to the primaryconversion zone.

3. A continuous process for convertinga relatlvely heavy hydrocarbonfraction containing substantially no gasoline into substantial yields ofsaturated gasoline of relatively high antiknock value which comprisescracking said heavy fraction at a temperature of from about 300 to about700 F. under a pressure of from about 50 to about 400 pounds per squareinch in the presence of aluminum chloride in an amount of less than 10%by weight of said hydrocarbon fraction and hydrogen chloride in anamount of from about 1 to 5% by weight of said hydrocarbon fraction in aprimary conversion zone to produce substantial yields of gasolineboiling range products, fractionating conversion products to producegases, gasoline, intermediate insufliciently converted refluxes andresidual material, recovering said gases and said residual material,returning said insufiiciently converted refiuxes to further conversion,subjecting said gasoline to further treatment at a temperature of fromabout 125 to about 500 F. with aluminum chloride in an amount of lessthan 10% by weight of said hydrocarbon fraction and hydrogen chloride inan amount of from about 1 to 5% by weight of said hydrocarbon fractionto improve the antiknock value thereof, fractionating the products fromthe gasoline treatment to produce gas, isomerized gasoline and residualmaterials consisting of hydrocarbon fractions amenable to furthercracking partly and spent aluminum chloride,'separately recovering saidgas and said isomerized gasoline and returning said residual material tothe primary conversion zone.

4. A conversion process which comprises cracking hydrocarbon oil heavierthan gasoline in the presence of aluminum chloride, fractionating theresultant products to separate gasoline fractions therefrom, subjectinggasoline fractions thus separated to further treatment with aluminumcholride'under reforming conditions to improve the anti-knock valuethereof, separating the reformed gasoline fractions from residualmaterial comprising partly spent aluminum chloride and hydrocarbonsamenable to cracking, and supplying at least a portion of said residualmaterial to the aforesaid cracking step.

- GUSTAV EGLOFF.

VASILI KOMAREWSKY.

